This invention relates to a scraper-conveyor apparatus for use in dumps, mixed-bed installations or the like, comprising a bridge, which is movable to be close to an end face of the dump and extends parallel to and approximately throughout the length of the base of the dump end face and carries a transverse conveyor, particularly an endless scarper chain, further comprising scraping means, which include a frame, that is connected to the bridge, and scraping ropes, which are connected to said frame and reciprocable parallel to the dump end face by drive means.
The known slope scraper-conveyor apparatus can be divided into three groups, namely:
(a) Slope scraper-conveyor apparatus in which the scraping means comprise a rigid harrow having rigid teeth and substantially covering the dump end face which is to be scraped. That harrow is reciprocated over a short distance along the dump end face;
(b) Slope scraper-conveyor apparatus in which the scraping means also comprise a rigid harrow which is set with rigid teeth but is narrow and must be moved over a distance corresponding to the length of the base of the dump end face;
(c) Slope scraper-conveyor apparatus having scraping ropes which at their upper end are secured to a frame and at their lower end are secured to a slide. The known slope scraper-conveyor apparatus of that kind comprise only a few ropes, which are tensioned by counterweights. For this reason the slide must be reciprocated virtually throughout the length of the dump end face.
The slope scraper-conveyor apparatus of groups (a) and (b) are not satisfactory in operation because when used with dumped materials which do not easily trickle because they are moist and tend to cake the teeth of the harrows form only grooves or narrow trenches in the dump end face and the resulting layers break off as soon as the grooves or trenches have a certain depth. As a result, the material is scraped off in a very irregular manner. This is highly undesirable because the transverse conveyors, which serve for the lateral conveyance of the material and in most cases consist of endless scraper chains, are then irregularly loaded with layers varying in thickness. Because with slope scraper-conveyor apparatus of group (b) the narrow harrow must move a long distance to act throughout the dump end face, the rate at which material is scraped off is unsatisfactorily low. A more uniform scraping action is performed by the slope scraper-conveyor apparatus of group (c) but they also do not act uniformly when handling dumped material which does not trickle easily and they cannot scrape off material at a sufficiently high rate because the movable rope ends must move other long distances. Besides, the reciprocating ropes are moved over long distances in the direction of conveyance of the transverse conveyor and opposite thereto in alternation so that the flight spaces of the conveyor are irregularly filled.